perilous

1 of 2

adjective

per·​il·​ous ˈper-ə-ləs 

ˈpe-rə-

: full of or involving peril

a perilous journey

perilously adverb

perilousness noun

perilousness

2 of 2

noun

per·​il·​ous·​ness

plural -es

: the quality or state of being perilous

Synonyms of perilous

Adjective

• dangerous
• hazardous
• risky
• serious

Choose the Right Synonym for perilous

dangerous, hazardous, precarious, perilous, risky mean bringing or involving the chance of loss or injury.

dangerous applies to something that may cause harm or loss unless dealt with carefully.

soldiers on a dangerous mission

hazardous implies great and continuous risk of harm or failure.

claims that smoking is hazardous to your health

precarious suggests both insecurity and uncertainty.

earned a precarious living by gambling

perilous strongly implies the immediacy of danger.

perilous mountain roads

risky often applies to a known and accepted danger.

shied away from risky investments

Examples of perilous in a Sentence

Adjective

a perilous journey across the mountains

a perilous journey through hostile territory

Recent Examples on the Web

Adjective

The Phillies survived their perilous five-day scare and are indeed headed to the playoffs for the fifth straight season after beating the Rays 7-3 to clinch the final NL wild-card berth. — CBS News, 28 Sep. 2026

Miéville is able to flex certain muscles—perilous for most fiction writers—in ways that support the dramatic tension rather than drain it. — Literary Hub, 24 Sep. 2026

The future is looking pretty perilous, and so people turn to spiritual matters. — Claire Hoffman, Rolling Stone, 21 Sep. 2026

Animals that bridge the human world and the wild can be uniquely perilous to human health, Dan Werb writes. — David A. Graham, The Atlantic, 18 Sep. 2026

Word History

Etymology

Adjective

Middle English perilous, perelous, borrowed from Anglo-French perilleus, perillous, going back to Latin perīculōsus, from perīculum "test, risk, peril entry 1" + -ōsus -ous

First Known Use

Adjective

14th century, in the meaning defined above

Rhymes for perilous

• carolus
• garrulous
• querulous
• puberulous

Kids Definition

perilous

adjective

per·​il·​ous ˈper-ə-ləs 

: full of or involving peril

perilously adverb

perilousness noun